1. Field of Invention
This invention relates to wearable sound-emitting devices that mask or cancel ambient sounds to help someone to sleep.
2. Introduction
Many people live in places that are increasingly noisy. The modern world is permeated by: intrusive sound systems with powerful bass speakers that penetrate apartment walls, video games with loud explosions and sound effects, vehicles with thumping bass speakers, jet and train traffic at all hours of the day and night, sirens and heavy equipment, dogs that bark incessantly, and so forth. The list of noise pollution sources grows each year. High noise levels are bad enough during daylight hours, but can be especially devastating at night when one is trying to sleep. Lack of sleep due to ambient sounds can wreak havoc on one's health, productivity, and overall quality of life. Sleep-disturbing sounds can even come from one's own household. For example, loud snoring can have devastating effects on one's closest personal relationships.
Some people can afford to live in places that are far removed from the flight paths of major airports, but other people cannot. Some people can afford to live far away from establishments that play loud music until the early morning hours, but other people cannot. Some people can afford to have living arrangements with multiple bedrooms so that they do not have to choose between a close relationship and getting enough sleep to face the next day, but other people cannot. For many people, sleep deprivation is a vicious cycle. Sleep deprivation hinders them from earning more income, the limited income limits their living options, and the limited living options result in more sleep deprivation. What can be done to break this cycle to help people to get a decent night's sleep in today's increasingly noisy world?
There is some prior art that is intended to reduce a sleeper's disturbance from ambient sounds. Much of this prior art involves sound “blocking,” sound “masking,” and/or sound “cancellation.” Sound “blocking” uses sound-insulating layers or structures to impede sound conduction and reduce the amount of ambient sound that reaches a sleeper's ears. Sound “masking” involves playing sounds to cover up ambient sounds. Many sound-masking devices create sounds with a broad-spectrum of frequencies, such as “white noise” or “pink noise,” to cover up ambient sounds at random. Other sound-masking devices offer a menu of sounds from which the sleeper can select to cover up particular ambient sounds.
Sound “cancellation” involves monitoring ambient sounds and custom-generating sounds that have a symmetrically-opposite wave structure to the ambient sounds. Ideally, when the ambient sound waves and the custom-generated sound waves overlap, their acoustic energies cancel each other out because their wave patterns are symmetrically opposite to each other. However, as we will discuss, the prior art in the area has significant limitations. There remains an unmet need for innovative devices to block, mask, or cancel ambient sounds to enable people to have a good night's sleep in noisy environments.